1. Field of the Invention
The present invention relates to a high-frequency module preferably applicable to a short-range radio data communication unit or the like.
2. Description of the Related Art
Conventional high-frequency modules will be described with the drawings. FIG. 14 is a perspective view showing the overview of a first form of a conventional high-frequency module. FIG. 15 is an enlarged plan view of principal parts of a circuit board of the first form of the conventional high-frequency module. FIG. 16 is a cross-sectional view of principal parts of a coaxial connector in the first form of the conventional high-frequency module. FIG. 17 is a schematic side view of the first form of the conventional high-frequency module. FIG. 18 is a plan view of a lower surface of the coaxial connector in the first form of the conventional high-frequency module. FIG. 19 is a plan view showing the circuit board on which the coaxial connector is mounted, in the first form of the conventional high-frequency module. FIG. 20 is a cross-sectional view showing an inspection status of the first form of the conventional high-frequency module.
FIG. 21 is a perspective view showing the overview of a second form of the conventional high-frequency module. FIG. 22 is an enlarged plan view of principal parts of a circuit board of the second form of the conventional high-frequency module. FIG. 23 is a cross-sectional view of principal parts of a coaxial connector in the second form of the conventional high-frequency module, showing a central conductor of the connector. FIG. 24 is a cross-sectional view of principal parts of the coaxial connector in the second form of the conventional high-frequency module, showing an external conductor of the connector. FIG. 25 is a plan view of a lower surface of the coaxial connector in the second form of the conventional high-frequency module. FIG. 26 is a plan view showing the circuit board on which the coaxial connector is mounted, in the second form of the conventional high-frequency module. FIG. 27 is a cross-sectional view showing an inspection status of the second form of the conventional high-frequency module.
Next, the first form of conventional high-frequency module will be described with reference to FIGS. 14 to 20. A wiring pattern 52 is formed on one surface (upper surface) side of a circuit board 51 made up of a print circuit board, and various electric components (not shown) are mounted on the wiring pattern 52, thus a desired electric circuit (transmission reception circuit) is formed.
A metal-plate cover 56 is attached to a necessary portion of the electric circuit, thus a part of the electric circuit is electrically shielded.
Further, a setting pattern 53 for setting a coaxial connector (to be described later) is formed on the circuit board 51.
As particularly shown in FIG. 15, the setting pattern 53 is constituted with four grounding lands 54 arranged in four corners of a square area and two lands 55a and 55b opposite to each other positioned between the grounding lands 54.
Although not shown here, the grounding lands 54 are connected to an grounding pattern of the wiring pattern 52. The one land 55a is connected to the electric circuit by a leading pattern 52a, and the other land 55b is connected to a connection pattern 52b for an antenna.
Further, an antenna 57 is mounted on the circuit board 51. The antenna 57 is connected to the wiring pattern 52 by the connection pattern 52b as a part of the wiring pattern 52.
As particularly shown in FIGS. 16 to 18, a coaxial connector 58 is constituted with an insulating base 59 made of an insulating material, an external conductor 60 attached to the outer periphery of an insulating base 59 in a status where the external conductor is supported (embedded) in the insulating base 59, and a pair of first and second central conductors 61 and 62 attached inside the insulating base 59 in a status where the central conductors are supported (embedded) in the insulating base 59.
The external conductor 60 has a cylindrical member 60a and four grounding electrodes 60b extended from the cylindrical member 60a and provided in four corners of a rectangular lower surface of the insulating base 59. Further, the first central conductor 61 has a fixed contact 61a exposed inside the insulating base 59 and an electrode 61b extended from the fixed contact 61a and provided in a central portion of one side of the lower surface of the insulating base 59. Further, the second central conductor 62 has a movable contact 62a which is exposed from a hole 59a at the center of the insulating base 59 and which is connectable/disconnectable to/from the fixed contact 61a and an electrode 62b extended from the movable contact 62a and provided in a central portion of another side of the lower surface of the insulating base 59.
Further, the first and second central conductors 61 and 62 are in contact with each other under normal conditions. When the movable contact 62a is depressed, the movable contact 62a is moved away from the fixed contact 61a and electrical continuity is broken. When the depression of the movable contact 62a is released, the movable contact 62a returns by its spring force and the both contacts become in electrical continuity. In this manner, the coaxial connector 58 is a so-called coaxial connector with switch.
The coaxial connector 58 having the above construction is mounted on the setting pattern 53 of the circuit board 51 and soldered to the setting pattern 53.
That is, as shown in FIG. 19, when the coaxial connector 58 is set, the four grounding electrodes 60b are respectively connected to the four grounding lands 54, the electrode 61b of the first central conductor 61 is connected to the land 55b and connected to the antenna 57, and the electrode 62b of the second central conductor 62 is connected to the land 55a and connected to the electric circuit.
At this time, the width of the grounding electrodes 60b and that of the grounding lands 54 are the same, and connected to each other as indicated by hatched portions in FIG. 19. The width of the electrodes 61b and 62b and that of the lands 55a and 55b are the same, and connected to each other as indicated by hatched portions in FIG. 19.
As a result, the antenna 57 is connected via the second central conductor 62 connected to the electric circuit and the first central conductor 61 provided between the antenna 57 and the second central conductor 62.
In the high-frequency module having the above construction, data transmission/reception is performed via the internal antenna 57.
Further, prior to shipment, various electrical inspections are performed on the high-frequency module. As shown in FIG. 20, an inspection member 63 made up of a coaxial connector is inserted into the coaxial connector 58 and the inspections are performed.
When the inspection member 63 is inserted into the coaxial connector 58, an external conductor 64 is connected to the external conductor 60, and the second central conductor 62 is depressed while a central conductor 65 is in contact with the second central conductor 62, so as to break connection with the first central conductor 61 and disconnect the first central conductor from the antenna 57.
In this status, a signal is sent from the inspection member 63 to the electric circuit for inspection of reception status, or a signal is sent from the electric circuit to the inspection member 63 for inspection of transmission status.
When the inspections have been completed, the inspection member 63 is removed, so that the first and second central conductors 61 and 62 return to the contact status.
Next, the construction of a second form of conventional high-frequency module will be described with reference to FIGS. 21 to 27. A wiring pattern 72 is formed on one surface (upper surface) side of a circuit board 71 made up of a print circuit board. Various electric components (not shown) are mounted on the wiring pattern 72, thus a desired electric circuit (transmission reception circuit) is formed.
A metal-plate cover 76 is attached to a necessary portion of the electric circuit, thus a part of the electric circuit is electrically shielded.
Further, a setting pattern 73 for setting a coaxial connector (to be described later) is formed on the circuit board 71.
As particularly shown in FIG. 22, the setting pattern 73 is constituted with two band-shaped grounding lands 74 provided to be opposite to each other with an interval therebetween, and one land 75 provided in a position a little away from the grounding lands 74.
Although not shown here, the grounding lands 74 are connected to an grounding pattern of the wiring pattern 72. The land 75 is connected to the electric circuit by a leading pattern 72a. 
In this second form of conventional high-frequency module, the connection pattern 52b for antenna in the first form of conventional high-frequency module is deleted.
As particularly shown in FIGS. 23 to 25, the coaxial connector 78 is constituted with an insulating base 79 made of an insulating material, an external conductor 80 attached to the outer periphery of an insulating base 79 in a status where the external conductor is supported (embedded) in the insulating base 79, and one central conductor 81 attached to the center of the insulating base 79 in a status where the central conductor is supported (embedded) in the insulating base 79.
The external conductor 80 has a cylindrical member 80a and two grounding electrodes 80b extended from the cylindrical member 80a and provided in opposed two corners of a rectangular lower surface of the insulating base 79. Further, the central conductor 81 has a cylindrical member 81a exposed in a hollow of the external conductor 80 and an electrode 81b extended from the cylindrical member 81a and provided in a central portion of one side of the lower surface of the insulating base 79.
Further, unlike the first form of conventional high-frequency module, the coaxial connector 78 is a coaxial connector without a switch.
The coaxial connector 78 having the above construction is mounted on a setting pattern 73 of the circuit board 71 and soldered to the setting pattern 73.
That is, as shown in FIG. 26, when the coaxial connector 78 is set, the two grounding electrodes 80b are respectively connected to the two grounding lands 74 and the electrode 81b of the one central conductor 81 is connected to the land 75 and connected to the electric circuit.
At this time, the width of the grounding electrode 80b and that of the grounding lands 74 are the same and connected to each other as indicated by hatched portions in FIG. 26, and the width of the electrode 81 and that of the land 75 are the same, and connected to each other as indicated by hatched portions in FIG. 26.
Further, when the high-frequency module having the above construction is used, the antenna 82 as a separate member is inserted into the coaxial connector 78. As a result, in the high-frequency module having this construction, data transmission/reception is performed via the antenna 82 as a separate member.
Further, prior to shipment, various electrical inspections are performed on the high-frequency module. As shown in FIG. 27, an inspection member 83 made up of a coaxial connector is inserted into the coaxial connector 78 and the inspections are performed.
When the inspection member 83 is inserted into the coaxial connector 78, an external conductor 84 is connected to the external conductor 80, and a central conductor 85 is in contact with the central conductor 81.
In this status, a signal is sent from the inspection ember 83 to the electric circuit for inspection of reception status, or a signal is sent from the electric circuit to the inspection member 83 for inspection of transmission status.
When the inspections have been completed, the inspection member 83 is removed, and the antenna 82 as a separate member is attached so that the module can be provided for use.
Generally, the high-frequency module has a first form as a module with antenna and a second form as a module without antenna. In the first form as a module with antenna, to disconnect the module from the antenna 57 upon inspection, the expensive coaxial connector 58 with a switch is used. Further, in the second form as a module without antenna, since it is not necessary to disconnect the module from the antenna upon inspection, the low-price coaxial connector 78 without a switch is used.
The circuit boards 51 and 71 used in the first and second forms of high-frequency modules are different from each other. Further, in the setting patterns 53 and 73 for setting the coaxial connectors 58 and 78, respectively specialized patterns are formed.
In the conventional high-frequency modules, as the circuit boards 51 and 71 in the first and second forms are different from each other, they must be separately manufactured at higher costs.
Further, as the circuit boards 51 and 71 in the first and second forms are different from each other, the specifications must be respectively certified, thus it takes a lot of trouble with the certification.